In copending application Ser. No. 541,699, filed June 21, 1990 now U.S. Pat. No. 5,025,101, there is disclosed a composition of matter having the formula M.sub.2 [Mn.sub.4 (O)(OH)(O.sub.2 CR).sub.2 L.sub.2 ] wherein M is an alkali earth metal selected from magnesium, calcium, strontium, barium or mixtures thereof, R is hydrogen or a hydrocarbyl group, and L is a ligand having the formula: ##STR1## These compounds have been shown to have a core structure of 4 manganese atoms which are bridged by oxo and hydroxo groups and, hence, they are referred to as oxo (hydroxo) bridged tetranuclear manganese compounds.
In copending application Ser. No. 580,413, filed Sept. 10, 1990 now U.S. Pat. No. 5,041,575, there is disclosed the conversion of the aforementioned oxo (hydroxo) bridged tetranuclear compounds into a hexadecanuclear manganese aggregate having the formula: EQU [Mn.sub.16 Ba.sub.8 Na.sub.2 ClO.sub.4 (OH).sub.4 (CO.sub.3).sub.4 (H.sub.2 O).sub.22 L.sub.8 ].xH.sub.2 O
wherein x is an integer ranging from 0 to about 32 and L is the ligand, (I), shown above.